Models and Dimensions of Earth I Model Simplified

Models and Dimensions of Earth I. Model= Simplified representation of an object or idea A. Types and Examples of Models: PHYSICAL 1. _________ - provides us with information through our sense of sight. Geographical Globe

Models and Dimensions of Earth Mechanical 2. _________ - a physical model with moving parts so that it can perform the functions or movements as the original model. Model Electric trains

Models and Dimensions of Earth Mathematical model - mathematical relationships 3. _________ expressed by symbols, formulas, and equations. Equations

Models and Dimensions of Earth Graphic model 4. _________ - a graph to provide a “picture” of a relationship of symbols, formulas, and equations. Temperature vs. Month Graph

Models and Dimensions of Earth Mental 5. _________ - models that can only exist in someone’s mind. Water is made of 2 Hydrogen and 1 Oxygen molecules

II. Shape of Earth Oblate spheroid - _________ Flattened sphere A. ________ Flattened at the poles 1. ___________ Bulging at the equator 2. ___________ Oblate spheroid 3. Diagram of an _____________ Polar diameter NOT TO SCALE Equatorial Diameter

greater 4. Earth’s equatorial circumference is _______ than its polar circumference. 24, 900 miles a. Equatorial circumference - __________ 24, 860 miles b. Polar circumference - ___________

B. Causes of Earth’s Shape Gravity 1. ___________ an inward pulling force. This force pulls equally in all directions and causes earth to be ____________. an oblate sphere Key______ = force of gravity .

Centrifugal Force 2. ________- an apparent outward force caused by the spinning (or rotating) of earth on its axis. This force causes earth to Rotate _________. faster a. The faster the rotational speed, the ______ the centrifugal force. b. (1) How long does it take each location to make one complete rotation? 24 hours X______ 24 hours Y______ X Y

(2) Which location, X or Y, travels a greater distance to make one complete rotation? ______ Location X (3) At which location, X or Y, is the rotational Location X speed greater? _______ (4) At which location, X or Y, is centrifugal Location X force greater? _______ c. Therefore, the greater centrifugal force causes Equator earth to bulge at the _____________. X Y

C. Evidence of Earth’s Shape 1. Photographs from space reveal that Earth is Round ____________ 2. Observations of ships on the horizon The gradual “appearance” or “disappearance” of a ship over the horizon is evidence that earth’s surface is __________. Curved

3. Observations of an Eclipse of the Moon (as viewed from Earth) a. As viewed from space: As the moon orbits Earth, and travels from position 1 to position 2, Earth’s shadow it passes through ___________________.

b. As viewed from Earth: c. Earth’s shadow on the moon (full moon) during a lunar eclipse provides evidence that Earth is _____________. Curved

4. Measurement of Gravity a. b. The shorter the distance between two objects, the greater the gravitational force. Therefore a person or object that is closer to the center of Earth (the center of gravity) would weight more than when the person or object is farther from the center of gravity.

c. (1) If Earth is an “oblate spheroid”, where on the surface of Earth would a person be closer to the center of Earth? At the poles _____________ (2) Where on the surface of Earth would a person weigh the most? At the poles _____________ d. Under what circumstance would a person weigh the same everywhere on Earth? If Earth was a perfect sphere.

5. Observation of North Star, Polaris a. The altitude of Polaris changes as an observer moves north or south (in the Northern Hemisphere); this is because Earth is _______, a sphere and its surface is ___________. curved (Altitude is the height, measured in degrees that a heavenly body is above the horizon of the observer).

Observer LATITUDE 1 2 3 4 90 ° North 90 ° 60 ° North 30 ° North 60 ° 0° ALTITUDE of POLARIS 30 ° 0°

c. Canada 60 ° N North Pole 90 ° N Alt. of Polaris 60 ° Altitude of Polaris = 90 ° 60 90 Atlanta 30 ° N Alt. of Polaris 30 ° 30 Equator 0° Alt. of Polaris 0° 0

d. Summary: Altitude of Polaris = Latitude As latitude increases altitude of Polaris increases. e. Locating the North Star NORTH STARPOLARIS

IV. Latitude and Longitude A. Latitude- The angular distance North or South of the equator. 1. Parallels- Lines that measure latitude that never touch. 2. Equator- Reference line for 0° latitude. Midway between both poles. 3. North/South Pole- Highest possible latitude, 90° North, 90° South 4. 90°North 60° North Arctic Circle 30°North Tropic of Cancer 0° Equator 30°South Tropic of Capricorn 60° South Antarctic Circle 90°South

IV. Latitude and Longitude B. Longitude- The angular distance East or West of the Prime • Meridians- Meridian. Lines of longitude that connect from pole to pole. • Prime Meridian- Reference line for longitude 0°, that goes through Greenwich England. • International Date Line. Largest possible longitude, 180°

Location 1 2 3 4 5 Latitude 30 ° North 45 ° South 0° 45 ° North 70 ° South Longitude 120 ° West 75 ° East 135 ° West 135 ° East 165 ° West

Location 6 7 8 9 10 Latitude 45 ° South 45 ° North 70 ° North Longitude 180° 15 ° South 75 ° West 0° 15 ° East 20 ° South 45 ° West

CONTINENTS A B C D E F G North America South America Europe Asia Africa Australia Antarctica

Oceans H I J K L Atlantic Pacific Indian Antarctic Arctic

D. Earth’s Time Zones 6 AM 1. As Earth rotates on its axis, half of earth is facing the sun and is experiencing daylight; the other half is in 12 darkness and is Noon experiencing night. 2. When the sun is directly over a certain meridian, it is 12 noon at any location at or near that meridian. 12 AM 6 PM

3. Think: Rate of Earth’s rotation ? Earth is a sphere/degrees in a circle = 360° = 15°/hr Time/ Hours to make one complete rotation = 24 hours 4. a. Number of time zones on Earth = 24 time zones b. Approximate width of each time zone = 15°

5. a. If it is Wednesday, and you cross the International Date Line going west, it would then be _________ Tuesday b. It is Tuesday, and you cross the International Date Line while traveling east, it would then be Wednesday _________

6. a. How many time zones are there in the continental U. S. ? 4 time zones _________ b. Is it earlier or later in California than New York? Earlier _________ c. If it is 8: 00 EST, what time is it in PST? 5: 00 _________ d. It is 6: 00 MST, what time is it in EST? 8: 00 __________